Libav
tree.c
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1 /*
2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of Libav.
5  *
6  * Libav is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * Libav is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with Libav; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include "error.h"
22 #include "log.h"
23 #include "mem.h"
24 #include "tree.h"
25 
26 typedef struct AVTreeNode {
27  struct AVTreeNode *child[2];
28  void *elem;
29  int state;
30 } AVTreeNode;
31 
32 #if FF_API_CONTEXT_SIZE
33 const int av_tree_node_size = sizeof(AVTreeNode);
34 #endif
35 
37 {
38  return av_mallocz(sizeof(struct AVTreeNode));
39 }
40 
41 void *av_tree_find(const AVTreeNode *t, void *key,
42  int (*cmp)(void *key, const void *b), void *next[2])
43 {
44  if (t) {
45  unsigned int v = cmp(key, t->elem);
46  if (v) {
47  if (next)
48  next[v >> 31] = t->elem;
49  return av_tree_find(t->child[(v >> 31) ^ 1], key, cmp, next);
50  } else {
51  if (next) {
52  av_tree_find(t->child[0], key, cmp, next);
53  av_tree_find(t->child[1], key, cmp, next);
54  }
55  return t->elem;
56  }
57  }
58  return NULL;
59 }
60 
61 void *av_tree_insert(AVTreeNode **tp, void *key,
62  int (*cmp)(void *key, const void *b), AVTreeNode **next)
63 {
64  AVTreeNode *t = *tp;
65  if (t) {
66  unsigned int v = cmp(t->elem, key);
67  void *ret;
68  if (!v) {
69  if (*next)
70  return t->elem;
71  else if (t->child[0] || t->child[1]) {
72  int i = !t->child[0];
73  void *next_elem[2];
74  av_tree_find(t->child[i], key, cmp, next_elem);
75  key = t->elem = next_elem[i];
76  v = -i;
77  } else {
78  *next = t;
79  *tp = NULL;
80  return NULL;
81  }
82  }
83  ret = av_tree_insert(&t->child[v >> 31], key, cmp, next);
84  if (!ret) {
85  int i = (v >> 31) ^ !!*next;
86  AVTreeNode **child = &t->child[i];
87  t->state += 2 * i - 1;
88 
89  if (!(t->state & 1)) {
90  if (t->state) {
91  /* The following code is equivalent to
92  * if ((*child)->state * 2 == -t->state)
93  * rotate(child, i ^ 1);
94  * rotate(tp, i);
95  *
96  * with rotate():
97  * static void rotate(AVTreeNode **tp, int i)
98  * {
99  * AVTreeNode *t= *tp;
100  *
101  * *tp = t->child[i];
102  * t->child[i] = t->child[i]->child[i ^ 1];
103  * (*tp)->child[i ^ 1] = t;
104  * i = 4 * t->state + 2 * (*tp)->state + 12;
105  * t->state = ((0x614586 >> i) & 3) - 1;
106  * (*tp)->state = ((0x400EEA >> i) & 3) - 1 +
107  * ((*tp)->state >> 1);
108  * }
109  * but such a rotate function is both bigger and slower
110  */
111  if ((*child)->state * 2 == -t->state) {
112  *tp = (*child)->child[i ^ 1];
113  (*child)->child[i ^ 1] = (*tp)->child[i];
114  (*tp)->child[i] = *child;
115  *child = (*tp)->child[i ^ 1];
116  (*tp)->child[i ^ 1] = t;
117 
118  (*tp)->child[0]->state = -((*tp)->state > 0);
119  (*tp)->child[1]->state = (*tp)->state < 0;
120  (*tp)->state = 0;
121  } else {
122  *tp = *child;
123  *child = (*child)->child[i ^ 1];
124  (*tp)->child[i ^ 1] = t;
125  if ((*tp)->state)
126  t->state = 0;
127  else
128  t->state >>= 1;
129  (*tp)->state = -t->state;
130  }
131  }
132  }
133  if (!(*tp)->state ^ !!*next)
134  return key;
135  }
136  return ret;
137  } else {
138  *tp = *next;
139  *next = NULL;
140  if (*tp) {
141  (*tp)->elem = key;
142  return NULL;
143  } else
144  return key;
145  }
146 }
147 
149 {
150  if (t) {
151  av_tree_destroy(t->child[0]);
152  av_tree_destroy(t->child[1]);
153  av_free(t);
154  }
155 }
156 
157 void av_tree_enumerate(AVTreeNode *t, void *opaque,
158  int (*cmp)(void *opaque, void *elem),
159  int (*enu)(void *opaque, void *elem))
160 {
161  if (t) {
162  int v = cmp ? cmp(opaque, t->elem) : 0;
163  if (v >= 0)
164  av_tree_enumerate(t->child[0], opaque, cmp, enu);
165  if (v == 0)
166  enu(opaque, t->elem);
167  if (v <= 0)
168  av_tree_enumerate(t->child[1], opaque, cmp, enu);
169  }
170 }
171 
172 #ifdef TEST
173 
174 #include "common.h"
175 #include "lfg.h"
176 
177 static int check(AVTreeNode *t)
178 {
179  if (t) {
180  int left = check(t->child[0]);
181  int right = check(t->child[1]);
182 
183  if (left > 999 || right > 999)
184  return 1000;
185  if (right - left != t->state)
186  return 1000;
187  if (t->state > 1 || t->state < -1)
188  return 1000;
189  return FFMAX(left, right) + 1;
190  }
191  return 0;
192 }
193 
194 static void print(AVTreeNode *t, int depth)
195 {
196  int i;
197  for (i = 0; i < depth * 4; i++)
198  av_log(NULL, AV_LOG_ERROR, " ");
199  if (t) {
200  av_log(NULL, AV_LOG_ERROR, "Node %p %2d %p\n", t, t->state, t->elem);
201  print(t->child[0], depth + 1);
202  print(t->child[1], depth + 1);
203  } else
204  av_log(NULL, AV_LOG_ERROR, "NULL\n");
205 }
206 
207 static int cmp(void *a, const void *b)
208 {
209  return (uint8_t *) a - (const uint8_t *) b;
210 }
211 
212 int main(void)
213 {
214  int i;
215  AVTreeNode *root = NULL, *node = NULL;
216  AVLFG prng;
217 
218  av_lfg_init(&prng, 1);
219 
220  for (i = 0; i < 10000; i++) {
221  AVTreeNode *node2 = NULL;
222  intptr_t j = av_lfg_get(&prng) % 86294;
223  void *ret, *jj = (void *)(j + 1);
224 
225  while (ret = av_tree_find(root, jj, cmp, NULL)) {
226  j = av_lfg_get(&prng) % 86294;
227  jj = (void *)(j + 1);
228  }
229 
230  if (check(root) > 999) {
231  av_log(NULL, AV_LOG_ERROR, "FATAL error %d\n", i);
232  print(root, 0);
233  return 1;
234  }
235 
236  if (!node)
237  node = av_tree_node_alloc();
238  if (!node) {
239  av_log(NULL, AV_LOG_ERROR, "Memory allocation failure.\n");
240  return 1;
241  }
242  av_tree_insert(&root, jj, cmp, &node);
243 
244  while (ret = av_tree_find(root, jj, cmp, NULL)) {
245  j = av_lfg_get(&prng) % 86294;
246  jj = (void *)(j + 1);
247  }
248 
249  ret = av_tree_insert(&root, jj, cmp, &node2);
250  if (ret != jj)
251  av_tree_destroy(node2);
252  ret = av_tree_find(root, jj, cmp, NULL);
253  if (ret)
254  av_log(NULL, AV_LOG_ERROR, "removal failure %d\n", i);
255  }
256 
257  av_tree_destroy(root);
258 
259  return 0;
260 }
261 #endif
Definition: lfg.h:25
memory handling functions
struct AVTreeNode * av_tree_node_alloc(void)
Allocate an AVTreeNode.
Definition: tree.c:36
void * av_tree_find(const AVTreeNode *t, void *key, int(*cmp)(void *key, const void *b), void *next[2])
Definition: tree.c:41
uint8_t
A tree container.
#define b
Definition: input.c:52
void av_tree_destroy(AVTreeNode *t)
Definition: tree.c:148
void * av_tree_insert(AVTreeNode **tp, void *key, int(*cmp)(void *key, const void *b), AVTreeNode **next)
Insert or remove an element.
Definition: tree.c:61
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:123
void av_free(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc(). ...
Definition: mem.c:186
error code definitions
struct AVTreeNode * child[2]
Definition: tree.c:27
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:168
int main(int argc, char **argv)
Definition: avconv.c:2608
int state
Definition: tree.c:29
#define FFMAX(a, b)
Definition: common.h:55
const int av_tree_node_size
Definition: tree.c:33
static av_always_inline int cmp(MpegEncContext *s, const int x, const int y, const int subx, const int suby, const int size, const int h, int ref_index, int src_index, me_cmp_func cmp_func, me_cmp_func chroma_cmp_func, const int flags)
compares a block (either a full macroblock or a partition thereof) against a proposed motion-compensa...
Definition: motion_est.c:255
NULL
Definition: eval.c:55
static unsigned int av_lfg_get(AVLFG *c)
Get the next random unsigned 32-bit number using an ALFG.
Definition: lfg.h:38
av_cold void av_lfg_init(AVLFG *c, unsigned int seed)
Definition: lfg.c:30
common internal and external API header
void av_tree_enumerate(AVTreeNode *t, void *opaque, int(*cmp)(void *opaque, void *elem), int(*enu)(void *opaque, void *elem))
Apply enu(opaque, &elem) to all the elements in the tree in a given range.
Definition: tree.c:157
void * av_mallocz(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:205
void * elem
Definition: tree.c:28
#define check(x, y, S, v)